AUTOMATIC CALIBRATION SYSTEM AND RELATED AUTOMATIC CALIBRATION METHOD APPLIED TO A CAMERA
An automatic calibration system applied to a camera and a related automatic calibration method are disclosed. The automatic calibration method utilizes a motionless calibration plate to calculate a calibration parameter of the camera, the camera includes at least one image sensing unit, and the camera is assembled with a testing device. The automatic calibration method includes rotating the camera by a first shaft and a second shaft of the testing device to change an angle of the at least one image sensing unit of the camera toward the calibration plate, capturing a plurality of images containing the calibration plate by the camera while rotating, calculating the calibration parameter of the camera according to the images, and storing the calibration parameter.
1. Field of the Invention
The present invention relates to a calibration system and calibration method applied to a camera, and more particularly, to an automatic calibration system and a related automatic calibration method capable of automatically executing calibration procedure to increase a calibration speed of the camera and economize testing space for calibration.
2. Description of the Prior Art
One of conventional calibrating methods applied to the camera is manually taking a calibration plate by an operator, moving the calibration plate to different locations before the camera to capture images containing the calibration plate performed by different view angles, and then calculating calibration parameters of the camera according to the images respectively performed by the dissimilar view angles; the said conventional calibrating method is in need of large space where the operator is allowed to hold the calibration plate and move in front of the camera. Another conventional calibrating method is displaying images on the computer screen, and each of the images represents the calibration plate performed in the corresponding view angle, so as to replace the calibrating method by manually moving the calibration plate before the camera; however, accuracy of the conventional calibrating method using the virtual calibration plate is limited to dimensions and resolution of the computer screen, and cannot provide sufficient accuracy as the calibrating method using the real calibration plate.
SUMMARY OF THE INVENTIONThe present invention provides an automatic calibration system and a related automatic calibration method capable of automatically executing calibration procedure to increase a calibration speed of the camera and economize testing space for calibration for solving above drawbacks.
According to the claimed invention, an automatic calibration method capable of utilizing a motionless calibration plate to calculate a calibration parameter of a camera is disclosed. The camera has at least one image sensing unit and is assembled with a testing device. The he automatic calibration method includes utilizing a first shaft and a second shaft different from each other to rotate the camera by the testing device so as to change an angle of the at least one image sensing unit of the camera toward the calibration plate, capturing a plurality of images containing the calibration plate by the camera while the camera is rotated, calculating the calibration parameter of the camera according to the plurality of images, and storing the calibration parameter.
According to the claimed invention, an automatic calibration system capable of calculating a calibration parameter of a camera is disclosed. The camera has at least one image sensing unit. The automatic calibration system includes a calibration plate, at least one testing device, a calculating unit and a storing unit. The calibration plate is disposed on a fixed location in a non-rotatable and non-movable manner. The at least one testing device is disposed by the calibration plate, and a distance between the testing device and the calibration plate is constant. The testing device is applied to support the camera and to rotate the camera by a first shaft and a second shaft different from each other, so as to change an angle of the at least one image sensing unit of the camera toward the calibration plate. The camera captures a plurality of images containing the calibration plate while being rotated by the testing device. The calculating unit is electrically connected to the camera and adapted to calculate the calibration parameter of the camera according to the plurality of images. The storing unit is electrically connected to the camera and adapted to store the calibration parameter.
The present invention disposes the camera on the testing device with biaxial rotation function. The testing device utilizes the first shaft and the second shaft as pivotal axes to change the angle of the image sensing unit of the camera toward the calibration plate. The automatic calibration method in the present invention does not move position of the calibration plate, so that testing space applied to the camera for the automatic calibration procedure can be accordingly economized; because the camera is rotated on the fixed location by the testing device, the camera does not change its location within the testing space, so the testing space can be further economized accordingly for the automatic calibration procedure. The automatic calibration system may utilize preset function of the testing device with the biaxial rotation function to rotate the camera being located at each of the predetermined angles in a programmable controlled manner, and drives the camera to automatically capture the images while being rotated to the predetermined angle, thus the automatic calibration system and the related automatic calibration method of the present invention can simultaneously control the plurality of testing devices via the central control host for execution of the calibration procedure. Comparing to the prior art, the present invention not only economizes the testing space where inside the testing device and the camera are locate, but also successfully increases calibration efficiency of the camera.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.
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The camera 20 utilizes the calibration parameter to calibrate the image captured by the camera; while the camera is the stereo camera with the multi-lens, the calibrated image further can be applied for depth estimation. The testing device 14 utilizes a first shaft 22 and a second shaft 24 as pivotal axes to rotate the camera 20, so as to change an angle of the at least one image sensing unit 28 (which is shown in
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It should be mentioned that the view range 32 of the camera 20 can be selectively divided into several uniform or various regions, an amount of the regions is not limited to the embodiment shown in
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During execution of step 504, the first predetermined angle, the second predetermined angle and the third predetermined angle respectively can be represented as, but not limited to, the first capturing direction N1, the second capturing direction N2 and the third capturing direction N3 shown in
In conclusion, the present invention disposes the camera 20 on the testing device 14 with biaxial rotation function. The testing device 14 utilizes the first shaft 22 and the second shaft 24 as pivotal axes to change the angle of the image sensing unit 28 of the camera 20 toward the calibration plate 12. The automatic calibration method in the present invention does not move position of the calibration plate 12, so that testing space applied to the camera 20 for the automatic calibration procedure can be accordingly economized; because the camera 20 is rotated on the fixed location by the testing device 14, the camera 20 does not change its location within the testing space, so the testing space can be further economized accordingly for the automatic calibration procedure. The automatic calibration system 10 may utilize preset function of the testing device 14 with the biaxial rotation function to rotate the camera 20 being located at each of the predetermined angles in a programmable controlled manner, and drives the camera 20 to automatically capture the images while being rotated to the predetermined angle, thus the automatic calibration system 10 and the related automatic calibration method of the present invention can simultaneously control the plurality of testing devices 14 via the central control host 26 for execution of the calibration procedure. Comparing to the prior art, the present invention not only economizes the testing space where inside the testing device and the camera are locate, but also successfully increases calibration efficiency of the camera 20.
Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.
Claims
1. An automatic calibration method capable of utilizing a motionless calibration plate to calculate a calibration parameter of a camera, the camera having at least one image sensing unit and being assembled with a testing device, the automatic calibration method comprising:
- the testing device utilizing a first shaft and a second shaft different from each other to rotate the camera, so as to change an angle of the at least one image sensing unit of the camera toward the calibration plate;
- the camera capturing a plurality of images containing the calibration plate while being rotated by the testing device;
- calculating the calibration parameter of the camera according to the plurality of images; and
- storing the calibration parameter.
2. The automatic calibration method of claim 1, wherein the testing device changes the angle of the at least one image sensing unit toward the calibration plate, and captures the plurality of images while the at least one image sensing unit and the calibration plate are in a non-coplanar mode.
3. The automatic calibration method of claim 1, wherein the testing device rotates the camera by the first shaft and the second shaft, to change a tilt angle of the at least one image sensing unit vertically toward the calibration plate and a rotary angle of the at least one image sensing unit laterally toward the calibration plate.
4. The automatic calibration method of claim 3, wherein the testing device rotates the camera to a predetermined specific angle by the first shaft and the second shaft, and the camera captures the plurality of images while the camera is set on the predetermined specific angle.
5. The automatic calibration method of claim 1, further comprising:
- dividing a view range of the camera into nine regions; and
- rotating the camera to respectively capture the plurality of images while the calibration plate is aligned with a middle region and two edged regions of the nine regions.
6. The automatic calibration method of claim 1, wherein the camera is a stereo camera having a plurality of image sensing units.
7. An automatic calibration system capable of calculating a calibration parameter of a camera, the camera having at least one image sensing unit, the automatic calibration system comprising:
- a calibration plate disposed on a fixed location in a non-rotatable and non-movable manner;
- at least one testing device disposed by the calibration plate, a distance between the testing device and the calibration plate being constant, the testing device being applied to support the camera and to rotate the camera by a first shaft and a second shaft different from each other, so as to change an angle of the at least one image sensing unit of the camera toward the calibration plate, wherein the camera captures a plurality of images containing the calibration plate while being rotated by the testing device;
- a calculating unit electrically connected to the camera and adapted to calculate the calibration parameter of the camera according to the plurality of images; and
- a storing unit electrically connected to the camera and adapted to store the calibration parameter.
8. The automatic calibration system of claim 7, wherein the testing device changes the angle of the at least one image sensing unit toward the calibration plate, and captures the plurality of images while the at least one image sensing unit and the calibration plate are in a non-coplanar mode.
9. The automatic calibration system of claim 7, wherein the testing device rotates the camera by the first shaft and the second shaft, to change a tilt angle of the at least one image sensing unit vertically toward the calibration plate and a rotary angle of the at least one image sensing unit laterally toward the calibration plate.
10. The automatic calibration system of claim 9, wherein the testing device rotates the camera to a predetermined specific angle by the first shaft and the second shaft, and the camera captures the plurality of images while the camera is set on the predetermined specific angle.
11. The automatic calibration system of claim 7, wherein a view range of the camera is at least divided into nine regions, the testing device rotates the camera by the first shaft and the second shaft, and the camera respectively captures the plurality of images while the calibration plate is aligned with a middle region and two edged regions of the nine regions.
12. The automatic calibration system of claim 7, wherein the automatic calibration system further comprises a plurality of testing devices and a central control host, the central control host comprises the calculating unit and the storing unit and is electrically connected to the plurality of testing devices, the central control host controls rotation of the plurality of testing devices according to a predetermined procedure to respectively calculate the calibration parameter of the camera corresponding to each of the plurality of testing devices.
13. The automatic calibration system of claim 7, wherein the camera is a stereo camera having a plurality of image sensing units.
Type: Application
Filed: Jul 4, 2016
Publication Date: Jan 19, 2017
Inventors: Cheng-Chieh Liu (New Taipei City), Szu-Mo Chang (New Taipei City), Yu-Kang Lin (New Taipei City), Sheng-Yuan Chen (New Taipei City)
Application Number: 15/201,516